1,4-bis-(tris(nf2)methoxy)-2-butene oxide and polymer thereof

ABSTRACT

1. THE COMPOUND 1,4-BIS-(TRIS(NF2)METHOXYL)-2-BUTENE OXIDE HAVING THE FORMULA:   2,3-BIS((NF2-)3-C-O-CH2-)OXIRANE   4. THE LIQUID POLYMERS OF POLYMERIC 1,4-BIS-(TRIS(NF2) METHOXY)-2-BUTENE OXIDE HAVING THE RECURRING MONOMERIC UNIT COMPOSITION:   -O-CH(-CH2-O-C(-NF2)3)-CH(-CH2-O-C(-NF2)3

United States Patent Oflice 3,564,023 1,4-BIS-(TRIS(NF )METHXY)-2-BUTENE OXIDE AND POLYMER THEREOF Eugene L. Stogryn, Fords, Joel G. Berger, Elizabeth, and

Lawrence J. Engel, Dunellen, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed July 29, 1964, Ser. No. 386,088 Int. Cl. C07c 93/10; C07d N18 US. Cl. 260-348 10 Claims This invention relates to the novel and useful compound 1,4 bis [tris(NF )methoxy] 2 butene oxide, polymers thereof, and their synthesis. This new epoxide which contains one NF group per carbon atom has the following structural formula:

The abbreviation FABDE is used to name this monomer. Because of the high NF -content (71%) and the reaction properties of this epoxide, it is adapted for use as an oxidizer or as an intermediate in the synthesis of useful higher molecular weight liquid and solid oxidizers, which are suitable components for advanced solid propellant formulations. The energetic epoxide can be prepared and isolated as either the cis or trans isomer. In making these high NE -content epoxides, the functional epoxide group through which polymerization can be effected is preserved, and the resulting polymers can be made to contain the same proportion of NE; as is present in the monomeric epoxides, even in an extensive polymerization to solid polymers.

With previously prepared NF -containing polymers of relatively low NF -content for use as oxidizer-binder components of solid rocket propellant formulations, the solid component of the binder has been kept generally in the proportion of 10 to 20 Wt. percent of the total formulations to obtain a high specific impulse value. With binders having less than one NF group per carbon atom, a serious loss of theoretical I at high binder content levels occurs. NOW, use of the polymers derived from FABDE enables formulations to be made with greater percentages of binder without significant loss of theoretical I A higher binder content permits a solid propellant formulation to have better physical and dynamic properties, i.e., greater strength, greater tenacity, less creep, etc.

In accordance with the present invention, the new high energy epoxide is prepared by reacting 1,4-dihydroxy-2- butene oxide, either the cis or trans isomer, with perfluoroguanidine in an adductive reaction, and the resulting adduct is fluorinated. The synthetic route is given as follows:

In this synthesis the starting reactant I is 1,4-dihydroxy-2- butene oxide. The perfluoroguanidine reactant 1s II, the

3,564,023 Patented Feb. 16, 1971 the adduct is III, and the fluorinated adduct termed FABDE is IV.

The perfluoroguanidine is a compound synthesized by fluorinating a salt of guanidine, e.g., guanidine carbonate, dissolved in distilled water at an adjusted pH, preferably 5 to 6, by addition of aqueous HP. The perfluoroguanidine undergoes an addition reaction with the hydroxy function, and in the present instance it was important to determine that the perfluoroguanidine addition and subsequent fiuorination would not destroy the epoxide ring.

The cis isomer of 1,4-dihydroxy-2-butene oxide is prepared by epoxidation of commercially available cis- 1,4-dihydroxy-2-butene. Using the cis isomer as the reactant I, the preparation of the hexakis NF derivative was made as described in the following example.

EXAMPLE 1 Preparation of cis-1,4-bis-[tris (NF )methoxy] -2- butene oxide (FAEDE) A pressure reactor was charged with 2.52 g. of cis 1,4-dihydroxy-2-butene oxide, 0.168 g. urea, ml. of acetonitrile, and 12 g. of perfiuoroguanidine. The reaction was stirred at room temperature overnight. After removal of the unreacted gases a F /N stream was passed over the surface of the acetonitrile solution for 4.5 hours. During the fiuorination the temperature in the reactor was maintained at 25 C.

After stripping off the acetonitrile the viscous residue was dissolved in Freon 113 or CCL; and dried with anhydrous Na CO The solution was filtered and the solvent blown off. The residue was placed on a silica gel column (the silica gel had previously been treated with caustic, H 0, and dried at 600 F. for 6 hours) with a minimum amount of CCl Elution with CCl gave 7.9 g. (74%) of cis-1,4-bis-[tris(NF )methoxyJ-Z-butene oxide having a purity of 96+%.The N.M.R. and infrared spectrum together with the elemental analysis proved the formation of the his adduct.

Calculated for C H O N F (percent): C, 16.45; N, 19.18; F, 52.03. Found (percent): C, 16.88; N, 19.31; F, 53.30.

To make the trans-FABDE the reactant, compound I, is the trans dihydric oxide Which was prepared by the epoxidation of trans-1,4dihydroxy-2-butene. The trans- 1,4-dihydroxy-2-butene is readily obtained from the caustic treatment of commercially available trans-1,4-dichloro-2-butene. The trans isomer reactant was used in making the hexakis NF derivative as shown in the following example.

EXAMPLE 2- Trans- 1 ,4-bis- [tris (N1 methoxy] -2-butene oxide A pressure reactor was charged with 0.45 g. of trans- 1,4-dihydroxy-2-butene oxide, 0.026 g. of urea, 6 ml. of acetonitrile, and 1.788 g. of perfiuoroguanidine. The reaction mixture was stirred at room temperature overnight. After removal of the unreacted gases a 10% F /N stream was passed over the surface of the reaction mixture for 2 hours at 0 C.

Working up the reaction product in a manner similar to that described in Example 1 yielded 1.4 g. (74%) of trans-1,4-bis-[tris(NF )methoXy]-2-butene oxide having a purity of Calculated for C H O N F (percent): C, 16.45; N, 19.18; F, 52.03. Found (percent): C, 16.95; N, 19.17; F, 53.4.

The infrared and N.M.R. spectrum are consistent with the structure for the trans isomer.

Containing a high proportion of NF the 1,4-bis-[tris- (NF )methoxy]-2-butene oxide monomer is in itself a monopropellant or oxidizer that may be used in a pro- 4 pellant formulation, but its epoxide function makes this plasticizer, the effect of raising the NF content of the compound particularly interesting for use in preparing 1,4-bis-[tris(NF )methoxy]-2-butene oxide polymer is polymers preferred as binders in a propellant formulashown in the following table. tion. It remained to be determined whether these mono- TABLE II.SOLID ROCKET mers could be polymerized satisfactorily to high molecular P ROPELLANT FORMULATION weight polymers or advantageously to solids without loss 3 355figgggg;Pgg gfi fifggggtgy of fluorine. In initial efforts to polymerize the epoxide e id z boron p fuel] monomer, a large number of catalysts were tried includ m ing PF PF -tetrahydrofuran, butyl lithium, triethyl po yme 2 aluminum, diethyl aluminum chloride, ethyl alumiw num dichloride, potassium hydroxide, sodium meth- 100/0 712 293-9 oxide, BF BF -Et O, titanium tetrachloride, stannic chloride, and others. In many attempts to polymerize there was difiiculty in obtaining polymers except with strong Lewis acids such as B1 TiCl or SnCl Various solvents polymer of ppr ximately 71% NF with an equal amount were used as media for the polymerization, e.g., liquid of Plasticizer having the composition S0 CH CI benzene, and others. Various polymeriza- (N 2)a 2 2 2 2 2)3 tio mod'fi rs W l d l d' 1,4-d'h d -2- n I e ere a so use Inc u mg 1 y foxy which contains 81.2% NF and with a difiuoramino 0x1- :Fhtx; eoggllcel tr1methylo1 Propane, epichlorohydrin and 0 dizer such as zhc HzhgNoz W-ith nitmnium per- EXAMPLES chlorate, a propellant compositlon having an I of 302 is obtained. In Examples 3 to 8 the FABDE and modifier and The composition of the 1,4-bis-[tris(NF )methoxy]-2- solvent, when indicated in Table I, were measured into butene oxide polymers without modifying agents and in a suitable container and the required amount of catalyst 5 its purest form is defined by the following formula which Using the 1,4-bis-[tris(NF )methoxy]-2-butene oxide was introduced at the prescribed temperature. After the gives the recurring monomeric unit: specified time the polymer was dissolved in methylene I" NF; NFz "I chloride, treated w1th aqueous Na CO and dried over Na CO The polymer was then isolated by removal of l- J the solvent. NFZ

TABLE I Mole Volume Mole Tempera- Time, Moi. Catalyst percent Solvent percent Modifier percent ture, 0. hrs. wt.

Example:

3 Shop 10 16 1,403 4 12 011201 DBOB 4 0,25 216 1,760 5 10 011201 50 25 72 1,460 B a 10 S02 50 TMP 5 25 16 2,825 7 SbOl 5 0112012 25 Glycerol 10 0, 25 2,120 1, 825

s 51001 2 H2O 10 25 18 s a DB 0 =1,4-dihydroxy-2-butene oxide.

b TMP=1,1,1-trimethy1o1 propane.

The hydroxyl content of the polymers was measured Two or more of these units may be linked together to and determined that the polymers contained sufficient form the polymers. These polymers may be made either hydroxyl groups to permit conversion to solid urethanes. from the cis monomer or the trans monomer. The polym- In the conversion to urethanes the liquid polymer was reerization temperatures used may be in the range of about acted with toluene diisocyanate, catalyzed by stannous 0 to 60 C. octanoate giving a stiff taffy consistency in 8 hours at The properties of these NF -containing butene oxide C. polymers have been extensively studied and compared wlth Although the solid plastic binders can thus be obtained other NF -polymers obtainable up to the present time. In from the liquid polymers of 1,4-bis-[tris(NF )methoxy]- determining the usefulness of these polymers as solid 2-butene oxide, it was finally found that this epoxide could 50 rocket propellant ingredients, they have been found to be polymerized into high melting point solids having the have exceptional important properties with respect to therdesirable high NF content. These high melting point mal stability, compatibility with available high-energy cosolid polymers and method of preparing them using prefingredients such as the leading plasticizer, hexakis(NF erably SbCl as the catalyst is described in the U.S. apdipropyl ether, the low sensitivity and exceptionally low plication Ser. No. 386,087 filed by D. S. Bosniack, E. L. impact sensitivity which is desirable for handling. Stogryn and I. G. Berger on July 29, 1964, now U.S. Pat. The solid NF -containing butene oxide polymer with a No. 3,441,520. It was found that this solid polymer has melting point of 202 to 204 C. in a vacuum thermal an excellent stability, high melting point, is easily prestability test evolved less than 2.7 cc. gas per gram of the pared and supplies a very useful solid for advanced solid polymer in 100 hours at 90 C. and evolved no gas at propellants which are to have I values from 290 to 100 hour at 60 C, above 300. These polymers are well adapted for use with A thermal stability test on the polymer plasticized with high NF -content liquid plasticizers being compatible the energetic oxidizer hexakis(NF )dipropyl ether evolved therewith, as for example, with hexakis(NF )propyl ether no more than 1.1 cc. of gas per gram in 100 hours at which has the formula: 60 C.

The solid polymer exhibited exceptional impact insensi- CH2(NF2) gg g )CH(NF )CH (NF tivity, measuring 23 kg. cm. It had one of the highest auto 2 2 2 2 ignition temperatures, 253 C. for a S-second induction This important oxidizer-plasticizer has been shown to be period, compared to other polymers of similar NF readily made by reaction of 1,2-divinyl ethylene oxide content. with N F as disclosed in U.S. application Ser. No. Based on reproducibility, obtainable use and simplicity 246,869, filed by E. L. Stogryn and M. H. Gianni on of preparation and of purification, these NF -containing Dec. 17, 1962. The hexakis(NF )propyl ether, which may butene oxide polymers were found outstanding compared also be more specifically named as di-[1,2,3-tris(NF )]nto other NF -containing polymers of similar NF content. propyl other can be prepared to have a high purity and In the properly catalyzed polymerizations of the mono high NF content of 76%. Using this compound as the mer, the conversion is high and can be substantially quan- 2. The compound cis-1,4-bis-[tris(NF )methxy]-2-butene oxide.

3. The compound trans-1,4-bis-[tris(NF )methoxy]-2- butene oxide.

4. The liquid polymers of polymeric 1,4-bis-[tris(NF methoxy]-Z-butene oxide having the recurring monomeric unit composition:

5. The method of preparing 1,4-bis-[tris(NF )methoxy]-2-butene oxide which comprises reacting cis-1,4-dihydroxy-Z-butene oxide with perfluoroguanidine to form a resulting adduct of the perfluoroguanidine therewith,

6 fiuorinating the resulting adduct to form cis-1,4-bis-[tris- (NF methoxy] -2-butene oxide.

6. The method of preparing trans-1,4-bis-[tris(NF methoxy]-Z-butene oxide which comprises reacting trans- 1,4-dihydroxy-2-butene oxide with perfluoroguanidine to form a resulting adduct and fiuorinating said adduct to obtain the trans 1,4 bis [tris(NF )methoxy]-Z-butene oxide.

7. The method of making the polymers of 1,4-bis-[tris- (NF )methoxy]-2-butene oxide which comprises polymerizing 1,4-bis-[tris(NF )methoxy]-2-butene oxide as monomer at temperatures in the range of about 0 to C.

8.. The method of claim 7, wherein a catalyst is present to catalyze the polymerization.

9. The method of claim 7, wherein the monomer is polymerized in a solvent.

10. The method of claim 7, wherein the monomer is polymerized with a reacting modifier present.

References Cited Hoffman et al.: Chem. Reviews, vol. 62, pp. 12-18 (1962).

LELAND A. SEBASTIAN, Primary Examiner US. Cl. X.R. 

1. THE COMPOUND 1,4-BIS-(TRIS(NF2)METHOXYL)-2-BUTENE OXIDE HAVING THE FORMULA:
 4. THE LIQUID POLYMERS OF POLYMERIC 1,4-BIS-(TRIS(NF2) METHOXY)-2-BUTENE OXIDE HAVING THE RECURRING MONOMERIC UNIT COMPOSITION: 